An increasing number of applications are requiring systems that employ a single antenna designed to receive from and/or transmit RF energy to multiple satellites positioned in several orbital slots broadcasting at multiple frequencies. In cases where the satellites are very close to each other, it creates a challenge for reflector antenna systems often resulting in compromised performance and/or increased cost and complexity. On a given reflector system, a feed horn or a radiating element is needed for each satellite to receive and/or transmit frequencies.
A typical mobile satellite antenna has a stationary base and a satellite-following rotatable assembly mounted on the base for two- or three-axis rotation with respect to the base. The assembly includes a primary reflector, a secondary shaped sub-reflector, and a low-noise block down-converter, and it may also include gyroscopes for providing sensor inputs to the rotatable assembly's orientation-control system. A typical configuration of this satellite antenna mounting approach is disclosed in U.S. Pat. No. 7,443,355.
U.S. Pat. No. 5,835,057 discloses a mobile satellite communication system including a dual-frequency antenna assembly. This system is configured to allow for the Ku band signals containing video and imagery data to be received by the antenna device and the L band signals containing voice/facsimile to be both received and transmitted by the antenna device on a moving vehicle.
U.S. Pat. No. 7,224,320 discloses an antenna device capable of reception from (and/or transmission to) at least three satellites of three separate RF signals utilizing a basic offset reflector on a stationary platform. This device allows for digital broadcast signals from digital video broadcast satellites in Ka, Ku and Ka frequency bands on the stationary platform.
U.S. Pat. No. 5,373,302 discloses an antenna device capable of transmission of three or more separate RF signals using a primary reflector and a frequency selective surface sub-reflector on a stationary platform. The device fails to disclose providing the antenna device on a moving platform and also fails to disclose any time of movement of the reflector including its components to track separate frequency signals.
Thus there is a need to provide an improved antenna system that allows for simultaneous reception of at least three or more television signals including at least two or more high definition television signals (HDTV) (as opposed to the digital signals of the prior art) on a moving platform.